Photoflash lamp and combination of matter



May 12,1970 a. KoPELMAN ETAL 3,511,535

'HoToFLAsH LAMP AND COMBINATION oF MATTER Filed Aug. 8, 1968 INVENTORS BERNARD KOPELMAN D A BY NALD SEEGER A TORNEY United States Patent O IntfCl. `F21k 5/ 02 US. (11....431--93 26 Claims ABSTRACT OF THE DISCLOSURE A` photoflash lamp including a light transmitting envelope having a container which can be shaped as a base disposed `at one end thereof. The envelope encloses a shredded combustible metal and a combustion supporting gas. A charge of a percussively ignitable composition of matter is disposed in the container, the interior of which is in communication with the interior of the envelope. Activation of the composition of matter is produced by striking the container with a hammer and in turn the shredded combustible metal will burn, thus flashing the lamp.

The ignitable composition includes percussively reactive materials which are associated relative to each other so as to ignite upon abrasive, interparticle movement. Such Vmaterials generally include at least a fuel and an oxidizer for the fuel. A powdered combustible, incandescible metal is operatively associated with and adjacent to the percussively reactive materials and adapted to incandesce `and then spew into the envelope to burn the shredded combustible metal when the reactive materials ignite.

CROSS REFERENCES TO RELATED APPLICATIONS This application is a continuation in part of our copending application, Ser. No. 662,756, iiled Aug. 23, 1967, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to photoash lamps having percussively ignitable compositions of matter adapted to flash such lamps included in their structure.

DESCRIPTION OF THE PRIOR ART Photoliash lamps have been known to the art and in the past, commercially available lamps were ilashed by passing current through coated tungsten igniter filaments which, when incandesced, ignited `and in turn, burned a shredded combustible metal disposed in the envelope. Incandescence of the filament was produced by an electric current from a battery associated with a camera. With prolonged standing, the battery sometimes became ineifective and the current produced by it was insutlicient to flash the lamp. Thus, upon snapping the shutter, the bulb would not ignite and a picture would be wasted.

It has previously been proposed to ash the lamp by means of mechanically activated, percussively ignitable compositions disposed in communication with the combustible metal retained in the envelope. The present invention is an improvement in such devices.

SUMMARY OF THE INVENTION We have discovered that if a combination of reactive materials is held in a metal container which is disposed at the end of a bulbous envelope, these -materials can be 3,511,586 Patented May 12, 1970 percussively ignited to reliably ash a shredded combustible metal. The shredded combustible metal can include any of those which are conventionally used in photoash lamps for photographic purposes.

The composition which is disposed within the container and that we have found to be reliable for igniting the shredded combustible metal includes percussively reactive materials, a fuel and an oxidizer, arranged to ignite upon interparticle movement, such as a blend of red phosphorous and potassium chlorate. Other fuels can include', for example,`sulfur, carbon, antimony sulfide and*V i lead thiocyanate and other oxidizers can include sodium chlorate, potassium perchlorate and potassium nitrate. Such blends react readily when the respective particles are rubbed together due to interparticle movement produced by striking the hammer upon the container. The above-mentioned mixtures of phosphorous and potassium chlorate are very sensitive to ignition by abrasion and are very effective in the lamp. Preferably, the Weight ratio of the fuel to the oxidizer, for example, is between about 1/ 9 to 9/1. The total quantity of P and KClO3 can be about 15 to 80 weight percent of the overall dry composition.

Intermixed with the percussively reactive materials is a powdered combustible, incandescible metal in quantities up to about 50 weight percent. We have found that a metal with a high heat of oxidation, such as zirconium, hafnium, thorium, aluminum, magnesium, boron, silicon or their alloys having particle sizes in the order of 0.5 to 5 microns easily cooperate to ignite the shredded combustible metal in the envelope. When the materials react, they ignite the powdered combustible, incandescible metal and force these incandescent particles to spew into the body of the envelope and ignite the shredded combustible metal.

In an embodiment of the invention, the composition is disposed between a foraminous anvil and the exterior of a cup which forms a base. When the composition ignites, the incandescent particles are forced through the foramina and into the body of the envelope to burn the shredded combustible metal. The anvil assists in preventing the composition from falling into the body of the lamp if it is inverted. Moreover, the anvil provides a rigid support for interparticle abrasion when the hammer strikes the cup portion. The foramina insure dispersion of the incandescent particles into the body of the envelope.

The quantities of the above-mentioned materials which are suicient to ignite the shredded combustible metal are not large. If such quantities are disposed in the container of some types of fiashlamps, they would be rather small in physical size and the base would have to be correspondingly small to retain them. However, a very small container would lead to high precision requirements and the areas which would be available for the hammer to strike would be reduced. Thus, the bulk size of the percussively ignitable composition in these larger lamps has to be increased so that the surface area of the container can be increased. Such increases, however, cannot be made solely by increasing the quantity of the percussively ignitable composition because large amounts can lead to explosive possibilities. `On the other hand, merely increasing the size with a filler might tend to reduce the sensitivity to activation of the percussively activatable materials in the composition. We have found that reliable ii-ashing of lamps having large containers can be attained through the addition of an inert but abrasive material such as, zirconia, silicon carbide, silica or alumina. The particle size of the ller should be :between about 10 to 200 microns and can be used in quantities up to about 50% by weight of the overall composition.

The effectiveness of the phosphorous is decreased if any of it is converted to phosphoric acid by lits reaction with any -moisture present. A small quantity of-a particulate material, capable of inhibiting the effect of phosphoric acid, can be added to the composition to prevent such loss of sensitivity. For example, an alkaline earth metal oxide such as magnesium oxide or aluminum oxide can be included in the composition in quantities up to about 1% by weight. Magnesium oxide, for example, reacts with the acids of phosphorus which are formed through the reaction with water and oxygen. The initial sensitivity can thus be maintained. A desiccant such as silica gel can also be added to remove any water which might have been inadvertently included in the lamp, either in the body of the envelope or in the composition.

The composition is held together with a binder. The quantity is suicient to retain the ingredients compactly, but insuticient to impregnate the particles and prevent interparticle abrasion, when the container is struck with a hammer.

As a variant to the above-described composition, it is possible to divide the ingredients into two portions when using a fuel and an oxidizer, such as red phosphorus and KClO3 as percussively activatable materials. One portion will contain the potassium chlorate and lthe other will contain the phosphorus. The balance of the ingredients can be -mixed with one and/or the other of these materials. For example, the potassium chlorate can be applied to` the bottom of the container as a slurry and a cake of the phosphorus and the other ingredients disposed upon the KClO3. The particles of the phosphorus and potassium chlorate will then be adjacent to each other and are activatable as described above.

The variant is desirable because of the extreme sensitivity of the mixture of red phosphorus and potassium chlorate, Iwhich creates problems when handling in production size quantities. While 'wet, either with water or organic solvents, the mixture is reasonably safe to handle, but when dry, it becomes extremely sensitive to mechanical stimuli. Inadvertent activations during manufacture of the lamp can be minimized and if any occur while the ingredients are damp, they will not be hazardous.

BRIEF DESCRIPTION OF THE DRAWING In the figure, a bulbous envelope is filled with oxygen at pressures in the order of 3 to 7 atmospheres and contains a filling of shredded combustible metal 2, for example zirconium. A metal base is hermetically sealed with a conventional glassto-metal seal 5 to envelope 1. At least one portion of cup 6 of the base is formed of a readily deformable metal, which in turn, will dent when a hammer (not shown) strikes it. The deformation fwill cause interparticle abrasion of the percussively activatable materials, such kas red phosphorus and the potassium chlorate contained in the charge 7. A rigidly disposed foraminous anvil 8 abuts against the charge 7 and holds it in place so as to prevent movement out of its confinement. Preferably, outwardly aring sides 9 are integrally attached to the Ianvil 8, so as to provide for rigid disposition, for example by a crimp 10.

When the percussively activatable materials are abrasively moved they will react and ignite the powdered combustible, incandescible metal which is mixed therewith. The incandescent particles of powdered metal (and some of the fuel) will spew through foramina 11 of the anvil 8 into the body of the envelope 1 where they will in turn ignite the shredded combustible metal 2 and cause the lamp to ash.

The charge 7 is held together with a binder such as hydroxyethylcellulose, nitrocellulose, or methoxycellulose. Preferably, the solids of the binder form about 1A to 4% by weight of the overall composition and are suiiicient to hold the particles forming charge 7 together as a unit, but insufficient to impregnate the body and coat the particles. The percussively activatable materials must be provided with interparticle moving space, whereby they can rub against each other and react. If vsuch movement were eliminated, or in the alternative, if each particle were coated, interparticle rubbing would be hampered.

As suitable ingredients for the composition, the following specific examples are given. These examples are intended to be `illustrative of the invention and not to be limitative upon the claims.

EXAMPLE I x Gms. P (Red) 0.27 KCIOS 0.270 MgO 0.002 Zr 0.45VY Inert -ller (Alundum) 0.65 (Nitrocellulose 2% by weight) 0.65

The composition is activated upon impact.

EXAMPLE -II A batch of the composition which can be subdivided is as follows:

Mgs.

P (Red) 14 KClO3 34 MgO 2 Silica gel 2 Alundurn 30 (Hydroxyethylcellulose solids) 2 The composition is activated upon impact.

It is Iapparent that modifications and changes can be made within the spirit and scope of the present invention, but it is our intention to be limited only by the appended claims.

As our invention, we claim:

1. A photoflash lamp comprising: a glass envelope containing a fill of combustion-supporting gas and shredded combustible metal; a container disposed at one end of said envelope, the interior of said container being in communication Iwith the interior of said envelope; a charge disposed in said container, said charge comprising particles of a percussively ignitable material and a powdered combustible, incandescible metal.

2. The lamp according to claim 1 wherein said percussively ignitable material includes a mixture of a fuel and an oxidizer.

3. The lamp according to claim 2 wherein the fuel is red phosphorus and the oxidizer is potassium chlorate.

4. The lamp according to claim 3 wherein the weight ratio of red phosphorus to potassium chlorate is between about 1/9 to 9/1.

5. The lamp according to claim 1 wherein the powdered metal portion of the charge is arranged relative to the rest of the charge so that it lwill incandesce and spew into the body of the envelope when ignited.

6. The lamp according to claim 1 wherein the powdered combustible, incandescible metal is at least one member from the group consisting of zirconium, hafnium, thorium, aluminum, magnesium, silicon, boron and alloys of these metals.

7. The lamp according to claim 6 wherein the particle size of the combustible, incandescible metal is between about 0.5 and 5 microns.

8. The lamp according to claim 1 wherein the charge includes a substance adapted to inhibit the oxidation of the phosphorus, thus preserving the initial sensitivity of the charge.

9. The lamp according to claim 8 lwherein said substance is lan alkaline earth oxide or aluminum oxide.

10. vThe lamp according to claim 1 wherein the particles of the charge are bound together by a binder, at least a portion of the surface of said particles being uncoated and free to abrasively rub one one Ianother whereby they can ignite.

11.i'[he lamp according to claim 1 wherein said charge is disposed in the base and abuts against a foraminous anvil separating at least a portion of said base from the interior of said envelope, said charge further abutting against a cup portion of said base, whereby when said cup` portion is struck, particles of said charge can ignite.

12.11The lamp according to claim 1 wherein either a wcoating of fuel or a coating of oxidizer is disposed upon the container and the other of the two materials is admixed `with powdered combustible, incandescible metal and disposed upon the coating.

13."A\photoash lamp comprising: a glass envelope containing a Ytill of combustion-supporting Vgas and shredded combustible metal; a container disposed at one end of said envelope, the interior of said container being in communication with the interior of said envelope; a charge disposed in said container, said charge comprising particles of a percussively ignitable material and a powdered combustible, incandescible metal together with particles of an abrasive, inert filler.

14.\The lamp according to claim 13 wherein said percussively` ignitable material includes a mixture of a fuel and an oxidizer.

15.? The lamp according to claim 14 wherein the fuel is red phosphorus and the oxidizer is potassium chlorate.

16. The lamp according to claim 15 wherein the weight ratio of red phosphorus to potassium chlorate is between about `1/9 to 9/1.

17." The lamp according to claim 13 wherein the powdered combustible, incandescible metal portion of the charge is arranged relative to the rest of the charge so that it will incandesce and spew into the body of the envelope when ignited.

18.:` The lamp according to claim 13 wherein the powdered combustible, incandescible metal is at least one member from the groups consisting of zirconium, hafnium, thorium, aluminum, magnesium, silicon, boron and` alloys thereof.

19..` The lamp according to claim 13 wherein the particle size of the combustible, incandescible metal is between about 0.5 to 5 microns.

20. The lamp according to claim 13 wherein the charge includes a substance adapted to react with the oxyacids of phosphorus, thus neutralizing them and preserving the initial sensitivity of the charge.

21.\ The lamp according to claim 20 iwherein said substance is an alkaline earth oxide or aluminum oxide.

22. The lamp according to claim 13 wherein the particles of the charge are bound together by a binder, at least a portion of the surface of said particles being uncoated and free to abrasively rub one another whereby they `can ignite.

23. The lamp according to claim 13 wherein said charge is disposed in a base and abuts against aV foraminous anvil separating at least a portion of said base from the interior of said envelope, said charge further abutting against a cup portion of said base, whereby when said cup portion is struck, particles of said charge can ignite.

24. The lamp according to claim 13 wherein either a coating of fuel or a coating of oxidiZ/er is disposed upon the container and the other of the two materials is admixed with powdered combustible, incandescible metal and disposed upon the coating.

25. The lamp according to claim 1 wherein the particles of percussively ignitible material are intimately admixed with the powdered combustible, incandescible metal.

26. The lamp according to claim 13 wherein the particles of percussively ignitible material are intimately admixed with the powdered combustible, incandescible metal.

References Cited UNITED STATES PATENTS 1,754,987 4/1930 Dri'ggs et al 102-32 2,024,225 12/ 1935 Igari 431-93 CHARLES J. MYHRE, Primary Examiner U.S. C1. X.R. 102-32; 431-269 

